//
//  Utils.swift
//  PrattParser
//
//  Created by 神经骚栋 on 2023/9/5.
//

import Foundation


extension String {
    func charAt(_ index: Int) -> String! {
        guard index >= 0 && index < count else {
            return nil
        }
        let wordIndex = self.index(self.startIndex,offsetBy: index)
        let word = self[wordIndex]
        return String(word)
    }
}
